A fisherman trawling off the Swedish island of Oeland netted a sturgeon from a species which had disappeared from the Baltic Sea a century ago, news agency TT reported Tuesday.Fisherman Ulf Aakerlund was at first stumped when he found the 78-centimeter (two-and-a-half-foot) fish in his nets last week."Initially I had no idea what it was. But when we looked it up on the Internet and looked in a few books we realised it was a sturgeon," he told TT.The specimen was an Atlantic sturgeon, or Acipenser oxyrhynchus, which was thought to have been extinct in the Baltic Sea since the early 1900s due to overfishing.But according to fish expert Mikael Svensson of the Swedish Species Information Centre, efforts have in recent years been made in Poland to breed sturgeon, and the specimen may have come from there."This is a good sign. It would be great if we could have this species in Swedish waters again. The sturgeon is a very special fish that doesn't resemble anything else we have in our waters," Svensson told TT.Atlantic sturgeon can grow as big as 4.5 meters (15 feet) and weigh 360 kilograms (795 pounds).The species is rare in European waters but is more common off North America's eastern coast.